A. Field of the Invention
The field of the present invention relates generally to motors for producing rotational torque through an output shaft that can be used to generate electricity or perform other work. More particularly, the present invention relates to such motors that utilize magnetic force to impart the rotational torque on the output shaft. Even more particularly the present invention relates to such motors that utilize a magnetically configured rotor of one pole that rotates within an involute-shaped stator of the opposite pole.
B. Background
Motors and other machines for converting a source of input energy to an output in the form of rotational torque that is delivered through an output shaft have been available for many years. The rotational torque at the output shaft is commonly utilized to produce electricity via a generator, power a pump, grinding wheel or other machine, turn a wheel, or operate other devices. The input energy for such machines has been provided by people, animals, moving water, gravity, blowing wind, fossil fuels, nuclear materials and a variety of other sources. Over the years, there has been a desire to have machines which utilize energy from readily available, clean and renewable sources. A favored source of such input energy is magnetic force, which is supplied by electromagnets and/or permanent magnets.
One type of machine is an electromagnetic reciprocating engine that utilizes electromagnetic force as the driving force to move a piston inside a cylinder to drive a crankshaft in order to produce motion or power. A typical configuration for such engines comprises a plurality of electrical coils disposed around the cylinder which are actuated by electrical currents to provide the electromagnetic force necessary to drive the piston in a reciprocating motion in the cylinder. This type of electromagnetic engine must have a somewhat large supply of electrical current to power the coils and typically requires a complex control mechanism to provide the electrical current to the coils in a manner so as to operate the engine. For these and other practical reasons, electromagnetic reciprocating engines have generally not become very well accepted.
Another source of power that has been utilized to reciprocate a piston inside a cylinder is the magnetic energy stored in permanent magnets. As is well known, when the same polarity ends of two magnets are placed near each other the repulsion force of the two magnetic fields will repel the magnets and, conversely, when the opposite polarity ends of two magnets are placed near each other the attraction force of the magnetic fields will attract the magnets toward each other, assuming one or both of the magnets are allowed to move. A known advantage of utilizing permanent magnets as the driving force for a reciprocating motor is that the energy available from these magnets is relatively constant and capable of providing a long operating life. In order to use permanent magnets to reciprocally drive a piston inside a cylinder, however, a mechanism must be provided that first utilizes the advantage of dissimilar polarity to attract the piston to the permanent magnet and then utilize the advantage of similar polarity to drive the piston away from the permanent magnet. Naturally, this must be done in a very rapid manner. The difficulties with being able to rapidly switch polarity when using permanent magnets, as opposed to electromagnetic force, has limited the ability to utilize the advantages of permanent magnets as a driving force to reciprocate a piston in a cylinder so as to rotate an output shaft for the purposes of motion or the generation of electricity.
Permanent magnets are also utilized in rotary magnet motors. The typical rotary magnet motor has a rotor with one or more magnets thereon that are configured to interact with a stator having one or more magnets thereon of an opposite polarity to promote rotation of the rotor about an axis that is generally perpendicular to the rotor and stator. Over the years, a variety of different rotary magnet motors have been developed that seek to benefit from the attraction and repelling action of the magnets, as discussed above, without the need to switch the polarity that is required for reciprocating type motors. An example of such a rotary magnet motor is found in U.S. Pat. No. 6,822,368 to Maslov, et al., which describes a rotary permanent magnet electric motor having salient stator poles with nonuniform pole thickness in the radial direction to compensate for the effects of clogging torque. A radial air gap of uniform thickness separates the stator poles and the permanent magnet pole shoes, which are varied in shape and/or position to achieve the desired results. U.S. Pat. No. 7,183,684 to Miyashita, et al. describes a permanent magnet rotary motor having a pair of end surfaces of each rotor permanent magnet are substantially parallel to a virtual plane that extends in the radial direction of the rotor core while passing through the centers of a stator core and an arc surface. U.S. Pat. No. 7,075,200 to Minato, et al. describes a direct-driven magnetic rotating apparatus that has permanent magnet plates mounted directly to a rotational body that is rotated by magnetic repulsive force. Numerous other examples of rotary magnet motors are known to those skilled in the art.
None of the foregoing prior art devices provides a rotary magnet motor that is particularly cost effective to construct and efficient to use to produce a rotary motion that can be utilized to accomplish a work task, such as turn a generator, power a fan, rotate a wheel and the like. What is needed, therefore, is an improved rotary magnet motor that utilizes magnetic attraction and repulsion to rotate a rotor and/or an output member to accomplish the desire work activity, such as generating electricity or powering a vehicle or other equipment. The preferred rotary magnet motor will utilize the benefits of permanent magnets to rotate the rotor, having magnets of one polarity, within the general confines of the stator, having magnets of the opposite polarity. Preferably, the rotary magnet motor will be relatively simple to operate, require a limited number of moving components and be relatively inexpensive to manufacture.